At least 13 pro-government fighters were killed in a rebel attack on their positions near the Yemeni capital despite a UN-brokered ceasefire taking effect this week, military sources said on Thursday.

The rebels attacked positions of Gulf-backed loyalist fighters in Nihm, northeast of Sanaa, where clashes have occurred for two weeks despite warring parties promising to abide by a ceasefire that took effect on Sunday at midnight.

A number of Iran-backed rebels were also killed in fighting that erupted after the Wednesday attack, loyalist military sources said.

The fragile truce is meant to pave the way for peace talks next Monday in Kuwait.

Military sources said on Wednesday that rebels had killed a senior loyalist officer and wounded six troops in Nihm.

Two pro-government fighters and a rebel were also killed in other clashes east of Sanaa.

In the southern loyalist-held province of Shabwa, rebels fired a mortar round on a village, killing three children aged between six and 10, according to a provincial official.